Yep. It's a Panel. And by the looks of it a 1 ton to boot.
The suburbans did have the glass windows in the sides as well as extra seating.
I drove a 1950 GMC panel as a daily for 3 years.
Torchie.
How cool! Friend of mine used to have one back in the days. We could carry the whole band and all the equipment and girlfriends and more! It also served as a break room in between sets. Somehow it was always smokey inside.